My folks do a split cabin flight to the US east coast a couple (might be more) of times a year. They do WT+ out, NCW back, this saves them 37,500 (18,750 per person) and say they actually prefer it that way.

I have told my dad to get a BAAmex and spend the £15k for a 2 for 1 voucher and then for roughly the same number of miles as he's paying now, both go First, both ways.